This specification relates to search query processing.
The Internet provides access to a wide variety of resources, for example, webpages, image files, audio files, and videos. These resources including content for particular subjects, book articles, or news articles. A search system can select one or more resources in response to receiving a search query. A search query is data that a user submits to a search engine to satisfy the user's informational needs. The search queries are usually in the form of text, e.g., one or more query terms. The search system selects and scores resources based on their relevance to the search query and on their importance relative to other resources, and provides search results that link to the selected resources. The search results are typically ordered according to the scores and presented according to this order.
Search engines are used to search corpora. As used herein, a corpus is a collection of resources. Each corpus can include resources of multiple types (e.g., a general web corpus can include HTML documents, images documents, videos, etc.; an image corpus, on the other hand, can be limited to a collection of images and metadata for the images). Thus there are different types of corpora that a search engine searches. For example, a search engine searches general resource corpus index to search resources based on the textual content of the resources and relative authority ratings of the resources. Search results resulting from a search of the general resource corpus index typically include a title of the resource, a snippet of text from the resource, and a link to the resource. Likewise, a search engine searches an image corpus index to search for images that are responsive to a search query. The image corpus index may index the images based on labels (or text) associated with the images, similarity of the images to other images, click through rates of images with respect to queries, and authority ratings of the images. Search results resulting from a search of the image corpus index typically include a thumbnail version of the image, an embedded link to the image, and optionally label text associated with the image.
Most search engines provide the users options to search a particular corpus. Some search engines also provide image search results with general search results. Typically these image search results are shown in a fixed configuration display area and show a fixed number of image search results that are responsive to a search query.